Does HashTable maintains the insertion order?

Question

The following code gives me the output in the same order of insertion. I read the javadoc and they did not even talk about the insertion order. Can someone help me to get the right information.

import java.util.*;  public class hash {  public static void main(String[] args) {      String str[] = { "japan",             "usa",             "japan",             "russia",             "usa",             "japan",             "japan",             "australia"};     int len = 8;     Hashtable ht = new Hashtable();     int i = 0;     while (i < len) {          String c = str[i];         System.out.println("c :" + c);         Integer intg = (Integer) ht.get(c);          if (intg == null)             ht.put(c, new Integer(1));         else             ht.put(c, new Integer(intg.intValue() + 1));          i++;     }      Enumeration k = ht.keys();      while (k.hasMoreElements()) {         String key = (String) k.nextElement();         System.out.println(key + " > " + ht.get(key));     } } } 

Answer 1

No, it does not. To preserve insertion order, instead use java.util.LinkedHashMap (javadoc).

Also, HashMap is now preferred over Hashtable, because Hashtable has unnecessary concurrency overhead. (See Differences between HashMap and Hashtable?.)

Answer 2

no, it does not. it only knows the "hash" order. if you reorder the strings, you will find they still appear in the same order from the hashtable.